Optimizing motion scaling and magnification in robotic surgery

BACKGROUND: Motion scaling is one possible advantage of robotic surgery. The aim of this study was to determine which scaling optimized precision and speed at different magnifications. METHODS: Three levels of motion scaling were tested at each of 3 camera magnifications. Surgically nave subjects (n = 12) were randomized as to the order of magnification level testing (3.5x, 6.5x, 9.5x) and motion scalings (10:1, 5:1, 1:1). The subjects were asked to pierce a needle through 6 printed microtargets; then accuracy and drill completion time were scored. RESULTS: At 3.5x magnification, no differences between groups were observed. At 6.5x magnification, the 5:1 scaling was superior to the 1:1 scaling in total errors, and the 10:1 scaling was significantly slower. At 9.5x magnification, 10:1 scaling resulted in fewer errors than 1:1 with no difference in time. Overall, the 10:1 and 5:1 scalings resulted in fewer errors. The 5:1 scaling resulted in less drill completion time than the 10:1 scaling. The 9.5x magnification resulted in the fewest errors. CONCLUSIONS: Motion scaling reduces the number of errors at higher magnifications, but can increase the task completion time. It is necessary to optimize both the motion scaling and magnification components of robotic systems to balance precision and speed.     

Hybrid robotic coronary artery surgery and angioplasty in multivessel coronary artery disease

BACKGROUND: Complete surgical revascularization that includes left internal thoracic artery grafting to the left anterior descending coronary artery remains the gold standard of treatment for coronary artery disease. Not all patients are good candidates for sternotomy. Therefore, we sought to identify a strategy that would combine the long-term advantages of internal thoracic artery grafting to lessen surgical trauma while still allowing complete revascularization. METHODS: A total of 54 consecutive patients from four institutions underwent hybrid revascularization combining surgery and angioplasty. All internal thoracic artery grafts were endoscopically harvested with robotic assistance using either the Aesop or Zeus system, and all anastomoses were manually constructed through a 4- to 6-cm anterior thoracotomy incision. Angioplasty was carried out to achieve total revascularization to ungrafted vessels. RESULTS: There were no early or late deaths, myocardial infarctions, strokes, or wound infections. Of the patients, 37 (69%) were extubated in the operating room. Length of stay in the intensive care unit averaged 24.4 hours and hospital stay 3.45 days. In all, 16 patients (29.6%) required transfusion of packed red blood cells. Late complications included 1 patient with stent occlusion at 3 months and 2 patients with in-stent restenosis. Three patients were treated for postpericardiotomy syndrome. Mean follow-up was 11.7 months. Event-free was survival 87.1% and freedom from recurrent angina 98.3%. CONCLUSIONS: Hybrid endoscopic atraumatic internal thoracic artery to anterior descending coronary artery graft surgery combined with angioplasty is a reasonable revascularization strategy in multiple vessel coronary artery disease in selected patients. Longer follow-up and more patient data in a randomized study are needed to determine the patient cohort most likely to benefit from this approach.     

Early experience with robotic technology for coronary artery surgery.

BACKGROUND: To achieve an endoscopic coronary bypass anastomoses we performed a study with endoscopic robotic instrumentation and camera guidance using three-dimensional (3-D) visualization. METHODS: The surgical robotic system ZEUS (Computer Motion Inc, Goleta, CA) consists of three interactive robotic arms and a control unit allowing the surgeon to move the instrument arms in a scaled down mode. The third arm (AESOP, Computer Motion Inc, Goleta, CA) positions the endoscope via voice control. The study had three phases. Phase I: In a phantom model, end-to-side anastomoses between vein grafts and the left anterior descending coronary artery (LAD) of 109 pig hearts were performed. Phase II: In 6 dogs (FBI, 20-25 kg) the left internal mammary artery (LIMA) was harvested endoscopically. During Port-Access (Heartport Inc, Redwood City, CA) cardiopulmonary bypass (CPB), LIMA and LAD were then anastomosed endoscopically with the help of telemetric ZEUS instruments (Computer Motion Inc). Phase III: A total of seven patients were operated on with help of the ZEUS system (Computer Motion Inc). After endoscopic LIMA harvesting and CPB using the Port-Access (Heartport Inc) system, the bypass graft (LIMA to LAD) was anastomosed endoscopically through three thoracic ports in 2 patients. Another 3 patients were operated on off-pump with regional stabilization and 2 patients with sternotomy and routine CPB. RESULTS: The practice with the phantom model and the subsequent animal experiments allowed the surgeons to gain sufficient experience for the clinical setting. In the clinical cases, times for anastomoses ranged from 20 to 42 minutes. Median internal mammary artery flow rate was 74 mL per minute (range 36-110 mL per minute). One patient in the off-pump group was converted to CPB and routine anastomosis. All patients had an uneventful angiographic control and postoperative course. CONCLUSIONS: Using telemetic technology, a completely endoscopic anastomosis of LIMA to LAD is possible on the arrested heart, as well as on the beating heart.     

Experimental off-pump coronary bypass using a robotic telemanipulation system.

We hypothesized that a high-quality anastomosis between the left internal thoracic artery and the left anterior descending coronary artery could be constructed off-pump using a 4-degrees-of-freedom robotic telemanipulation system, endoscopic myocardial stabilization, and two-dimensional visualization. Nine swine were used. Three ports were created on the left chest for the endoscope and the two robotic arms, and another port was created on the right chest for the endostabilizer. Quality of anastomosis was assessed by angiography, analysis of flow, survival after proximal coronary ligation, and histopathology. All nine anastomoses were completed successfully in 22 +/- 3.6 minutes without the need for repair stitches. Left internal thoracic artery flow was 21.6 +/- 2.5 ml/min with diastolic dominant pattern. Eight animals (89%) survived for 60 minutes with the proximal left anterior descending coronary ligated. Angiographic patency was 100% with Fitzgibbon grade A in all. Histopathology of the anastomosis demonstrated minor changes in the integrity of the endothelium and the internal elastic lamina and absence of medial necrosis. We have demonstrated in our robotic off-pump coronary bypass model that a high-quality anastomosis can be constructed between the left internal thoracic artery and the left anterior descending coronary artery. These results support continued research towards robotic endoscopic off-pump CABG.     

Evaluation of robotic minimally invasive surgical skills using motion studies

Robotic Minimally Invasive Surgery, and the engendered computer-integration, offers unique opportunities for quantitative computer-based surgical-performance evaluation. In this work, we examine extension of traditional manipulative skill assessment, having deep roots in performance evaluation in manufacturing industries, for applicability to robotic surgical skill evaluation. This method relies on: defining task-level segmentation of modular sub-tasks/micro-motions called ‘Therbligs’ that can be combined to perform a given task; and analyzing intra- and inter-user performance variance by studying surgeons’ performance over each ‘Therbligs’. Any of the performance metrics of macro-motions—from motion-economy, tool motion measurements to handed-symmetry—can now be extended over the micro-motion temporal segments. Evaluation studies were based on video recordings of surgical tasks in two settings: first, we examined performance of two representative manipulation exercises (peg board and pick-and-place) on a da Vinci surgical SKILLS simulator. This affords a relatively-controlled and standardized test-scenarios for surgeons with varied experience-levels. Second, task-sequences from real surgical videos were analyzed with a list of predefined ‘Therbligs’ in order to investigate its overall usefulness.     

Comparison between angiographic right coronary artery motion and echocardiographic tricuspid annulus motion

OBJECTIVE: To compare echocardiographic M-mode measurements of tricuspid annulus motion (TAM) with angiographic M-mode measurements of right coronary artery motion (RAM). DESIGN: Twenty-four patients were included and examined by echocardiography before the angiographic examination. The amplitudes and the velocities of TAM and the atrial contribution to the total amplitude of TAM were measured. The obtained values were compared with angiographic M-mode measurements of RAM at a proximal and a distal site of the second segment of the right coronary artery. RESULTS: There was no significant difference between several of the echocardiographic M-mode measurements of TAM and the angiographic M-mode measurements of RAM. However, the agreement was rather poor for some variables. CONCLUSION: Different parameters obtained from echocardiographic TAM are not interchangeable with values from angiographic RAM. If measurements of RAM are to be used in the assessment of right ventricular (RV) function further studies are needed to examine the correlation and agreement between RAM and different methods of measuring RV function, i.e. radionuclide angiography or magnetic resonance imaging.     

Optimization of vessel orientation for robotic coronary artery bypass grafting

The availability of telemanipulation robots has not yet resulted in the emergence of a reliable endoscopic coronary bypass procedure. A major challenge in performing a closed-chest coronary operation is creating a high-quality anastomosis in a reasonable period of time. In this experimental study, the impact of distal vessel orientation on the speed and accuracy of anastomosis was quantifed. We found that vessel orientation and the relative angle of the surgical plane influence anastomosis speed, the trauma to the vessel, the accuracy of stitch placement, and the eventual achievement of hemostasis. Our results suggest that the speed and accuracy of a robotically performed anastomosis of a vessel graft to a coronary artery can be improved by making small changes in vessel orientation. Vessels should be positioned between the horizontal and diagonal orientation and inclined between the horizontal and +45 degrees . Because the 6-o'clock stitch is particularly challenging, surgeons may benefit from an orientation that moves the heel or the toe of the anastomosis away from this critical position.     

Vessel pathology and its clinical significance in toe transfer.

One hundred cases of toe transfer were subjected to histopathologic vessel examination. Results indicated that vascular injuries are crucially responsible for perioperative and postoperative crisis. A thorough resection of the abnormal vessel segment can prevent circulatory crisis and elevate the survival rate.     

全机器人胸廓内动脉游离非体外循环冠状动脉旁路移植术

目的总结全机器人下不开胸胸廓内动脉（IMA）游离心脏不停跳冠状动脉旁路移植术的初步经验。方法使用da Vinci S全机器人系统,完成胸廓内动脉游离心脏不停跳下冠状动脉旁路移植术15例。所有患者均有心绞痛症状,其中4例患者有心肌梗死病史,冠状动脉造影显示严重的前降支病变,2例患者对角支及回旋支亦有病变。手术过程中于左侧胸壁打直径为1cm的器械臂孔3个,医生于操作台前在三维成像系统下操控机器人进行胸廓内动脉的游离,其中13例行左侧胸廓内动脉游离,1例行双侧胸廓内动脉游离,1例行对侧胸廓内动脉游离。游离结束后,沿左胸前第4肋间行长度为6cm小切口开胸,13例于心脏跳动下行胸廓内动脉和前降支的吻合,2例同时吻合对角支或回旋支。其中1例是完全机器人不停跳下冠状动脉旁路移植术。结果所有患者均成功接受胸廓内动脉游离,无胸廓内动脉损伤及术式的转变。胸廓内动脉和前降支、对角支和回旋支吻合后桥血流良好。术中平均出血量80ml,平均ICU时间20h,术后恢复好。结论全机器人不开胸胸廓内动脉游离技术精细、安全,不停跳下冠状动脉移植术效果确实、可靠,术后效果良好。     

The significance of coronary arterial stenosis during cardiopulmonary bypass.

Myocardial infarction may develop during an uneventful open-heart operation. In order to better understand this complication, we undertook an experimental study. The left circumflex coronary artery of 20 dogs was narrowed to 50 per cent of its area by a metal screw clamp to produce a localized coronary stenosis. Regional myocardial perfusion in the distribution of both the stenotic circumflex and normal left anterior descending (LAD) coronary arteries was measured by injection of a radioactive-labeled microsphere (15 +/- 5 mu). Circumflex coronary artery flow was measured with an electromagnetic flow probe. An epicardial electrogram was recorded in the distribution of the left circumflex. Measurements of regional myocardial perfusion, circumflex flow, and the epicardial electrogram were performed in each animal during the control (prebypass) state and during cardiopulmonary bypass with a beating and fibrillating ventricle. Half the animals had cardiopulmonary bypass performed at 50 mm. Hg perfusion pressure and half at 100 mm. Hg. The animals were put to death at the end of the study, and the hearts were sectioned, weighed, and counted. A cast was made of the stenotic circumflex coronary artery, the degree of stenosis is measured, and the per cent area stenosis calculated. The study showed that the effect of a 50 per cent coronary stenosis in reducing distal flow is apparent only during cardiopulmonary bypass at reduced pressure. The mechanism whereby a myocardial infarction develops during cardiopulmonary bypass could evolve from the development of a "critical" stenosis out of a mild-moderate one at a reduced perfusion pressure during cardiopulmonary bypass.     

Hybrid coronary revascularization: Midterm outcomes of robotic multivessel bypass and percutaneous interventions

Objective

The purpose of this study was to investigate the outcomes of patients undergoing advanced hybrid coronary revascularization, defined as robotic beating-heart multivessel totally endoscopic coronary artery bypass combined with percutaneous coronary intervention.

Septal wall motion. Its significance on outcome of left ventricular scar resection

To assess the importance of septal wall motion on patient outcome after resection of large akinetic and dyskinetic segments of left ventricle, the records of 70 patients undergoing left ventricular scar excision alone or in combination with myocardial revascularization procedures between January 1970 and January 1977 were reviewed. Patients requiring simultaneous prosthetic valve replacement were excluded. Preoperative left anterior oblique ventriculograms categorized this series of patients into two distinct groups, group A (36 patients) having normal septal wall motion and group B (34 patients) having akinetic or dyskinetic septal walls. Indications for operation and preoperative ejection fractions were similar in both groups. Analysis of these patients subjected to surgery with and without preoperative evidence of septal wall motion demonstrated no significant difference in either functional clinical capacity or in mortality. Mortality for both groups was 11%. Absence of ventricular septal wall motion has no significant effect on outcome of left ventricular scar resection and should not be used as a contraindication to surgery.     

The clinical significance of coronary angioscopy in patients with coronary heart disease

Summary The feasibility and safety of coronary endoscopy was evaluated in three sets of investigations: in 7 cadaver hearts, in 11 patients undergoing coronary bypass surgery, and in 30 patients during routine cardiac catheterization prior to coronary balloon angioplasty (PTCA). In three of the seven cadaver hearts the lumen of the arteries appeared normal. In three diffuse atherosclerotic lesions, and in one, a high-grade, tight stenosis were observed. In nine of eleven patients in the operation room, the lesions of interest could be visualized, and high-grade stenoses were found in all. In addition, in three patients with unstable angina pectoris, fresh thrombi were seen at the site of stenosis. In six of the nine patients, the periphery of the native coronary vessel was found to have no further stenotic regions. During cardiac catheterization in 17/30 patients, the lesion of interest could be examined angioscopically, and in 13 instances the stenosis appeared excentric and irregularly shaped. In three instances, multiple ulcerations were seen in the stenotic area. In two of the five patients, intimal ruptures were found following PTCA, which could not be documented angiographically. Coronary endoscopy provides valuable additional information on the nature and appearance of atherosclerotic lesions. It can be performed clinically without great harm to the patients. Despite some limitations, it will probably become a routine diagnostic tool in patients undergoing routine coronary angiography, balloon angioplasty or high-frequency angioplasty, and coronary bypass grafting.     

A new exposure technique for the circumflex coronary artery system in robotic totally endoscopic coronary artery bypass grafting

We report a case of a 53-year-old female patient with isolated left main coronary artery stenosis in whom a completely endoscopic double coronary artery bypass grafting (CABG) procedure was performed. The operation was carried out on the arrested heart. A right internal mammary artery graft was sutured to the left anterior descending artery using the daVinci telemanipulation system. The left internal mammary artery was connected to the first obtuse marginal branch which was exposed with the Octopus-TE stabilizing device. This method may be useful for further development of multivessel totally endoscopic CABG procedures.